The invention relates to the field of electrical lighting fixtures. More particularly, the invention is related to ceiling and wall-mounted tube-type lamp mounting fixtures, such as those employed to hold fluorescent lamp tubes.
Fluorescent lamp tubes have been used to light schools, offices and industrial sites for decades. Recently, the need to provide more efficient lamps has driven the design of new tube-type lamps that emit either the same or higher lumen energy using less electrical power than previous lamps. For example, those skilled in the art will recognize that older T-8 and T-12 lamps can be replaced by new T-5 lamps that can emit more lumens of light energy while consuming less power than their older and larger predecessors.
One consequence of the popularity of the new T-5 lamp is the need for new mounting assemblies. The T-5 is not only a smaller diameter lamp tube, but it is also slightly shorter than its older counterparts and will not fit in a mounting assembly (or xe2x80x9creflectorxe2x80x9d or xe2x80x9cfixturexe2x80x9d) that was designed for the T-8 and T-12 lamps. Thus, if a facility manager decides to change over from T-8 or T-12 lamps to T-5 lamps, it has been necessary to replace all of the reflector assemblies in a facility so that the smaller, shorter T-5 lamp can be installed. As a consequence, replacing old lamps has required replacement of old fixtures as well, a cost factor that acts as a disincentive to changing from the older, less efficient lamps to the newer and much more efficient types.
The present invention is a conversion apparatus that enables the conversion of a standard fluorescent lamp reflector fixture to accommodate the newer T-5 lamp without replacement of the entire fixture. In use, the invention features a pair of identical conversion apparatus, each having one or more plug/receptacle combinations. The plug/receptacle combinations are situated on opposite surfaces of a bar, the plug on one side and the receptacle on the other. The plug is sized for the original size light tube for which the lamp assembly was designed; that is, if the fixture was intended for T-8 tubes, the plug(s) on the adapter is(are) a T-8 sized plug. The receptacle (also referred to as xe2x80x9csocketxe2x80x9d), located on the opposite side of the bar, is sized to receive the new, smaller and shorter lamp, such as a T-5. The bar contains wiring to connect the plug and the receptacle, providing the energizing electrical power signal from the lamp ballast to the lamp(s). Two of the conversion apparatus are mounted in a lighting fixture to change the fixture""s configuration from the older lamp size to accommodate the newer lamps.
Another important feature of the apparatus of the invention is that the plug and receptacle combinations, though mounted on opposite sides of the bar, are mounted independent from each other. Each can be moved laterally along the bar without regard to the position of the other. In this manner, variations in the spacing of the receptacles in a mounting fixture can be accommodated by adjusting the position of the plugs on the adjustable conversion apparatus. In the same fashion, the ultimate positioning of the new lamp tubes relative to each other can be set by adjusting the location of the receptacles on the conversion apparatus.
The invention further comprises a series-connected master-slave ballast configuration and cable apparatus. In the conversion of an existing fluorescent lamp assembly to a new configuration, new electronics are installed in the lamp fixture to convert the ballast in the existing fixture to provide the appropriate power for the new lamp tubes. The old ballasts remain and provide the basic power signals. New circuit boards are installed in the fixture to provide the correct power supply, heater and oscillator signals to the new lamps. A shield for protecting the circuit boards is provided for installation in the existing fixture along with the plug/receptacle conversion assembly. A series connection cable designed specifically for connecting the new circuits to provide a master-slave ballast configuration is also provided.